Pilots Troy Asher and Wayne Ringelberg walk out of NASA’s Armstrong Flight Research Center’s (AFRC) hangar in Palmdale, California, toward the flight line. via NASA https://ift.tt/2Nc3kHr

This artist’s concept shows an astronaut on Mars, as viewed through the window of a spacecraft. via NASA https://ift.tt/2N4cBRB

Seen here in incredible detail is the starburst galaxy formally known as PLCK G045.1+61.1. The galaxy, which appears as multiple reddish dots near the center of the image, is being gravitationally lensed by a cluster of closer galaxies, also seen in the image. via NASA https://ift.tt/37BHlmp

Launched on April 20, 2004, Gravity Probe B (GP-B) was a collaboration between Stanford University and NASA designed to test two previously untested aspects of Albert Einstein’s general theory of relativity. via NASA https://ift.tt/3d5BRlg

Looking deep into the universe, the Hubble Space Telescope catches a passing glimpse of the numerous arm-like structures that sweep around this barred spiral galaxy, known as NGC 2608. Appearing as a slightly stretched, smaller version of our Milky Way, the peppered blue and red spiral arms are anchored together by the prominent horizontal via NASA https://ift.tt/30zSbbl

This illustration imagines the view from NASA’s Cassini spacecraft during one of its final dives between Saturn and its innermost rings. via NASA https://ift.tt/3fcESSc

Like a wisp of green smoke, the aurora australis seemingly intersects with the Earth’s airglow as the International Space Station orbited above the Indian Ocean halfway between Australia and Antarctica. via NASA https://ift.tt/2YjVTmx

Japan’s resupply ship, the H-II Transfer Vehicle-9 (HTV-9), is pictured attached to the International Space Station’s Harmony module. via NASA https://ift.tt/3dIA9Hz

Exquisite layering is revealed emerging from the sand in southern Holden Crater. Sequences like these offer a window into Mars’ complicated geologic history. via NASA https://ift.tt/37c8bBu

The stars of the globular cluster NGC 6441 sparkle peacefully in the night sky, about 13,000 light-years from the Milky Way’s galactic center. via NASA https://ift.tt/2MzbFo5